Reading disability: Evidence for a genetic etiology

A review of evidence for genetic influences on reading disabilities (RD) is presented, with focus on twin study design and sib-pair linkage techniques. DeFries-Fulker multiple regression analyses result in significant estimates of heritability for group deficits on several reading and language measures. Structural equation modeling techniques reveal the presence of significant common and independent genetic effects on individual differences on reading skills. Finally, linkage techniques confirm a candidate locus for RD on chromosome 6.     

Life course impacts of parenting a child with a disability

We contrasted parents who had a child with a developmental disability, a serious mental health problem, and a normative comparison group with respect to parental attainment and well-being at mid-life. Data are from the Wisconsin Longitudinal Study, collected when the respondents were 18, 36, and 53 or 54, on average. Although similar at age 18, group patterns of attainment and well-being diverged thereafter. Parents of a child with a developmental disability had lower rates of employment, larger families, and lower rates of social participation but were similar to parents without a child with a disability in educational and marital status, physical health, and psychological well-being. Parents whose child had a serious mental health problem had normative patterns of educational and occupational attainment and marriage, but elevated levels of physical symptoms, depression, and alcohol symptoms at mid-life.     

Axonal pathology in multiple sclerosis: relationship to neurologic disability.

In this review, data is summarized supporting the hypothesis that axonal loss is a major pathologic process responsible for irreversible neurologic disability in patients with multiple sclerosis. Pathologic studies implicate inflammatory demyelination as a principal cause of axonal transection and subsequent axonal degeneration. Axonal degeneration caused by chronic demyelination in the absence of active inflammation may also contribute to progressive disability in the later stages of the disease. Studies using magnetic resonance spectroscopy suggest that axonal loss begins at the onset of the disease, and studies using magnetic resonance imaging have documented brain atrophy in the earliest stages of multiple sclerosis. Brain atrophy increases during the relapsing-remitting disease stage without concurrent disability progression. This suggests that compensatory mechanisms maintain neurologic function, despite progressive brain tissue loss during the early stages of the disease. Beyond a threshold, however, further axonal loss leads to continuously progressive neurologic disability. We hypothesize that the rate and extent of axonal loss during relapsing-remitting multiple sclerosis determines when a patient enters the secondary progressive stage of the disease. This view of disease pathogenesis has several important implications. First, surrogate markers of axonal loss are needed to monitor the disease process for patient care and for clinical trials. We propose brain parenchymal fraction, a precise measure of whole-brain atrophy, as an attractive candidate for this purpose. Second, disease-modifying therapy should be used early in multiple sclerosis patients, before extensive axonal loss has occurred. Third, neuroprotective drugs should be tested in combination with anti-inflammatory drugs in multiple sclerosis patients. Finally, studies of the time course of axonal loss, and its mechanisms are critical for effective therapeutic intervention.     

Reading disability: Spatial frequency specific deficits in visual information store

Visual information store durations for sine-wave gratings were measured in normal and disabled readers. At low spatial frequencies, disabled readers have significantly longer store durations; at medium spatial frequencies, the two groups do not differ; and at high spatial frequencies, disabled readers have shorter store durations.     

Family quality of life among families with a child who has a severe neurodevelopmental disability: Impact of family and child socio-demographic factors

We aimed to examine family quality of life (FQOL) of Northern Israeli families having a child with a severe neurodevelopmental disability and its relation to socio-demographics. The cohort included caregivers of 70 children ages (mean ± standard deviation) 5.36 ± 3.53 years. Families were two-parent (85.7%), lived in the periphery (67.1%) and included Jews (60%), Muslims (18.6%), Druze (14.3%) and Christians (7.1%). Religiosity included: secular (38.6%), traditional (31.4%), religious (30%). Children's diagnosis included autistic spectrum disorder (41.4%), intellectual disability (21.4%), cerebral palsy (17.1%), genetic syndromes (17.1%) and sensorineural hearing loss (2.9%). Degree of support (1-minimal,5-greatest) required by the child was 3.67 ± 1.28 for physical and 3.49 ± 1.36 for communication. Primary caregivers completed the FQOL Survey. Domain scores were highest for family relations and lowest for financial well-being. Dimension scores were highest for importance and lowest for opportunities. Overall FQOL approximated average. Jewish families and residents of a major urban area reported higher and more religious families reported lower overall FQOL. Regression analysis found ethnicity contributing to overall FQOL and domain scores with residence contributing to support from services. Ethnicity and child dependence contributed to dimension scores. Northern Israeli families having a child with a severe neurodevelopmental disability report average FQOL scores. However, family and child dependence characteristics affect FQOL scores. Professionals working with these families should consider FQOL information when making recommendations.     

Stepping Stones Triple P seminars for parents of a child with a disability: a randomized controlled trial

Parents of children with a developmental disability require tailored parenting support, as their families have special needs and are at risk of increased burden. The aim of this study was to evaluate the efficacy of the Stepping Stones Triple P seminars, a brief group intervention for parents of a child with a disability. There were two seminars that presented parenting strategies to improve both child behavior and parenting variables implicated in the development and maintenance of child problem behavior. Fifty-three parents participated in this randomized controlled trial. Each had a child, aged two to ten, with a disability. The results indicated significant reductions in child behavior problems, the use of dysfunctional parenting styles, and parental conflict reported by parents in the intervention group compared to a waitlist group. The results were maintained at 3-month follow-up and there was evidence of a sleeper effect for parenting confidence. This study demonstrated that the seminars provide a promising intervention for parents of children with a disability. Limitations and implications for future research are also discussed.     

Explaining the parental stress of fathers and mothers caring for a child with intellectual disability: a Double ABCX Model

BACKGROUND: Twenty variables based on the Double ABCX Model of adaptation and selected on the basis of previous research were chosen to explain the parental stress of the mothers (n = 116) and fathers (n = 120) of children with an intellectual disability (age range = 1- 10 years). METHODS: Principal component analysis, rotated into varimax-criterion, was done separately for mothers and fathers. The solution containing eight factors was considered best for both groups. They accounted for more than 70% of the total variance of the original variables. These eight orthogonal components were then entered into a stepwise regression analysis that was done separately for mothers and fathers. RESULTS: The multiple regression equations obtained explained 72% of the variance in maternal stress and 78% of the variance in paternal stress. The equations for mothers and fathers contained six and seven components, respectively. CONCLUSIONS: The variables used in the present study were highly successful in accounting for parental stress. The results confirm the importance of intervening factors in explaining the stress. The single most important predictor of parental stress was the negative definition of the situation. In mothers, the negative definition was associated with the behavioural problems of the child while, in fathers it was connected with the experienced social acceptance of the child.     

Mechanisms underlying the effects of prenatal psychosocial stress on child outcomes: beyond the HPA axis

Accumulating evidence from preclinical and clinical studies indicates that maternal psychosocial stress and anxiety during pregnancy adversely affect child outcomes. However, knowledge on the possible mechanisms underlying these relations is limited. In the present paper, we review the most often proposed mechanism, namely that involving the HPA axis and cortisol, as well as other less well-studied but possibly relevant and complementary mechanisms. We present evidence for a role of the following mechanisms: compromised placental functioning, including the 11β-HSD2 enzyme, increased catecholamines, compromised maternal immune system and intestinal microbiota, and altered health behaviors including eating, sleep, and exercise. The roles of (epi)genetics, the postnatal environment and the fetus are also discussed. We conclude that maternal prenatal psychosocial stress is a complex phenomenon that affects maternal emotions, behavior and physiology in many ways, and may influence the physiology and functioning of the fetus through a network of different pathways. The review concludes with recommendations for future research that helps our understanding of the mechanisms by which maternal prenatal stress exerts its effect on the fetus.     

Distressed neighborhoods and child disability rates: analyses of 157,000 school-age children

The aim of this study was to assess rates of childhood disability as indicated by functional limitation of motor, sensory, or self-care skills in children living in severely-distressed neighborhoods. For a neighborhood in the US Census Track to be considered severely distressed, three of the following four characteristics need to be present: >27% of children live in poverty, >23% high school drop-out rate, >34% male unemployment rate, and >37% of households headed by females alone. In the 2000 US Census, 157 000 children between ages 5 and 15 years resided in the State of Rhode Island. Severely-distressed neighborhoods were found in 12.6% of Rhode Island Census Tracks. These areas accounted for 14.5% of the school-age population, 25% of children with motor disabilities, 29% of children with self-care disabilities, and 14% of children with sensory disabilities. For each increasing level of neighborhood distress, rates of child disability increased. Child disability rates in moderately distressed neighborhoods were 3.7%, compared with 1.1% in advantaged neighborhoods. Children in distressed neighborhoods had disproportionately high rates of disability, especially in motor and self-care functioning. Comprehensive interventions aimed at children in distressed neighborhoods are crucial to reduce health disparities for vulnerable children.     

Onset of maternal psychiatric disorders after the birth of a child with intellectual disability: A retrospective cohort study

Mothers of a child with intellectual disability (ID) have more psychiatric disorders after the birth of their child than other mothers. However, it is unclear if this is because they have more psychiatric disorders before the birth or if the increase is related to the burden of caring for the child. We aimed to calculate the rate of new psychiatric disorders in mothers after the birth of their eldest child with ID born between 1983 and 2005 and to compare these with rates in women with a child with no ID or autism spectrum disorder (ASD) born during the same period. By linking data from Western Australian population-based registries, we selected women with no psychiatric history who survived the birth of their live-born child (N = 277,559) and compared rates of psychiatric disorders for women with a child with ID and women without a child with or ASD. Negative binomial regression with STATA 12 was used for all analyses. Mothers of children with mild–moderate ID of unknown cause had around two to three and a half times the rate of psychiatric disorders of mothers of children without ID or ASD. Mothers of children with Down syndrome and no pre-existing psychiatric disorder showed resilience and had no impairments in their mental health. Interventions and services are needed for mothers of other children with ID to improve their mental health. Further research is implicated to explore the mental health of mothers of children with ID and a pre-existing psychiatric disorder.